all: InterestHeader and ContentObjectHeader refactoring to Interest and ContentObject

refs #29
diff --git a/examples/custom-apps/dumb-requester.cc b/examples/custom-apps/dumb-requester.cc
index 3dbcadf..643e24c 100644
--- a/examples/custom-apps/dumb-requester.cc
+++ b/examples/custom-apps/dumb-requester.cc
@@ -90,14 +90,14 @@
   
   Ptr<ndn::Name> prefix = Create<ndn::Name> (m_name); // another way to create name
 
-  // Create and configure ndn::InterestHeader
-  ndn::InterestHeader interestHeader;
+  // Create and configure ndn::Interest
+  ndn::Interest interestHeader;
   UniformVariable rand (0,std::numeric_limits<uint32_t>::max ());
   interestHeader.SetNonce            (rand.GetValue ());
   interestHeader.SetName             (prefix);
   interestHeader.SetInterestLifetime (Seconds (1.0));
 
-  // Create packet and add ndn::InterestHeader
+  // Create packet and add ndn::Interest
   Ptr<Packet> packet = Create<Packet> ();
   packet->AddHeader (interestHeader);
 
@@ -112,7 +112,7 @@
 }
 
 void
-DumbRequester::OnContentObject (const Ptr<const ndn::ContentObjectHeader> &contentObject,
+DumbRequester::OnContentObject (const Ptr<const ndn::ContentObject> &contentObject,
                                 Ptr<Packet> payload)
 {
   NS_LOG_DEBUG ("Receiving ContentObject packet for " << contentObject->GetName ());